The present application claims priority to Japanese Application No. P10-294155 filed Oct. 15, 1998; Japanese Application No. P10-311057 filed Oct. 30, 1998 and Japanese Application No. P10-371006 filed Dec. 25, 1998 which applications are incorporated herein by reference to the extent permitted by law.
1. Field of the Invention
The present invention relates to the method for manufacturing a semiconductor device and retrofitting of a semiconductor device and more particularly to a semiconductor manufacturing method and a semiconductor device based on the structure of a semiconductor substrate disposed on a printed wiring board (PWB).
2. Description of the Related Art
Digital video cameras, digital portable telephones, and portable electronic equipment such as notebook type personal computers has recently been widely popular and this has increased the need for smaller, thinner, and more lightweight portable equipment.
To realize the size reduction, thinning, and weight reduction of the portable equipment, the increase in part mounting density is an important problem.
In particular, a high density mounting technique has been developed and put to practical use. In the technique, a flip-chip semiconductor device has been used as a semiconductor device such as a semiconductor IC instead of a package semiconductor device.
There is provided a method for mounting such a flip-chip type semiconductor device (flip-chip mounting), that is, for example, such a method that solder ball bumps are formed on the A1 electrode pad, and respective connection terminals of the semiconductor IC chip are made to abut on the solder ball bumps, and the IC chip is then mounted directly on the printed wiring board.
There is provided a method by using electrolytic plating as a method for manufacturing the above mentioned solder balls. According to this method, there is a problem that since the thickness of solder deposited by electrolytic plating is affected by the state of the surface of a primary material layer and slight fluctuation of electric resistance, it is fundamentally difficult to form solder ball bumps with even heights in one IC chip.
As a method for manufacturing solder ball bumps so as to correct the unevenness of the heights of the solder ball bumps, there is provided film deposition by vacuum deposition and pattern forming of photoresist films using lift-off method.
Such methods are carried out for example as shown in FIG. 4.
First, as shown in FIG. 9A, the electrode 1 for a flip-chip type semiconductor IC 1 is formed in the following manner.
The electrode section la comprises an electrode pad 3 comprised of Alxe2x80x94Cu alloy formed on a semiconductor substrate 2 comprised of silicon by sputtering and etching, a silicon oxide film formed on the electrode pad 3 so as to cover the whole surface of the semiconductor substrate 2, a surface protection film 4 comprised of polyimide, an opening 4a formed in the region of the electrode pad 3 of the surface protection film, and a ball limiting metal (BLM) film 5, that is, a metallic multilayer film comprised of, for example, Cr, Cu, Au, and so on which is formed by sputtering so as to cover the surface of the electrode pad 3 exposed at the side and bottom of the opening 4.
To form a solder ball bump on the electrode 1a of the semiconductor IC chip 1, as shown in FIG. 9B, a resist film 6 having an opening 6a in the region of the above BLM film 5 is formed.
Subsequently, as shown in FIG. 9C, a solder deposition film 7 is deposited on the resist film 6 so as to cover the whole surface of the semiconductor substrate 2.
After that, as shown in FIG. 9D, by lift-off of the resist film 6, unnecessary portions of the solder deposition film 7 is removed to form a desired pattern of the solder deposition film.
Lastly, as shown in FIG. 9E, by melting the solder of the solder deposition film 7 by thermal treatment, almost spherical solder ball bump 7a is formed based on the surface tension of solder.
In view of the above points, it is an object of the present invention to provide the semiconductor device and the method for manufacturing the same which enable thin and lightweight electronic equipment and realize high reliability and best functions of the electronic equipment.
According to the present invention, thin and lightweight electronic equipment can be manufactured and there can be provided a semiconductor device and the method for manufacturing the same with high reliability and high performance.
According to the first aspect of the present invention, the above object can be attained by the semiconductor device having: a semiconductor chip in which a first protrusion electrode is formed on the semiconductor substrate; and an intermediate substrate which comprises a base substrate, a first external terminal provided in the base substrate, which is joined to the first protrusion electrode, a second external terminal provided in the base substrate, an electrode section being exposed on both surfaces of the base substrate, and a second protrusion electrode formed at one end face of the second external terminal, a plurality of the intermediate substrates being stacked in layers by joining the second protrusion electrode to the other end face of the second external terminal.
According to the configuration of the first aspect, the semiconductor-chip-mounted intermediate substrates are stacked in layers by connecting the second protrusion electrode and the second outer terminal. This reduces the length of wiring between semiconductor chips, enabling high-speed signal processing with inductance reduced. Further, stacking semiconductor chips in layers can realize higher density mounting than two-dimensional mounting, enabling manufacturing small-sized and lightweight semiconductor devices and further manufacturing small-sized and lightweight electronic equipment.
According to the second aspect of the present invention, the above object can be attained by a semiconductor device in the configuration of the fist aspect, wherein thinning is adopted for the surface of the semiconductor chip on which the first protrusion electrode is not formed in the semiconductor substrate to thin the semiconductor substrate.
According to the configuration of the second aspect, a semiconductor chip is processed by grinding, polishing, and etching so that the thickness of the semiconductor chip is reduced. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the third aspect of the present invention, the above object can be attained by a semiconductor device in the configuration of the second aspect, wherein the thickness of the semiconductor chip is formed into approx. 200 xcexcm or less.
According to the configuration of the third aspect, the semiconductor chip is processed to approx. 200 xcexcm or less. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the fourth aspect of the present invention, the above object can be attained by a semiconductor device in the configuration of the first aspect, wherein the thickness of the base substrate of said intermediate substrate is formed into approx. 200 xcexcm or less.
According to the configuration of the fourth aspect, the intermediate substrate is processed to approx. 200 xcexcm or less. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the fifth aspect of the present invention, the above object can be attained by a semiconductor device in the configuration of the first aspect, wherein resin is filled on the surface where the first protrusion electrodes are formed in the semiconductor chip.
According to the configuration of the fifth aspect, filling resin around the first protrusion electrode increases the strength of connection between the first protrusion electrode and the base substrate, thus enabling improving the reliability of the semiconductor device.
According to the sixth aspect of the present invention, the above object is attained by a semiconductor device in the configuration of the first aspect, wherein the thickness in the direction of stacking in layers in the second protrusion electrode is formed into approx. 300 xcexcm or less.
According to the configuration of the sixth aspect, the second protrusion electrode is processed in the direction of stacking in layers so that the thickness reaches approx. 300 xcexcm or less. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be effectively miniaturized removing surplus space and can be lightened.
According to the seventh aspect of the present invention, the above object is attained by the method for manufacturing a semiconductor device in which: a first protrusion electrode is formed on the surface of a semiconductor substrate, and a semiconductor chip manufactured thin is joined to a first external terminal provided for the base substrate of an intermediate substrate, a second protrusion electrode is formed at one end of a second external terminal whose electrode is exposed at both surfaces of the base substrate, the second external terminal being provided for the base substrate of the intermediate substrate, and a plurality of the intermediate substrates are stacked in layers by joining the second protrusion electrode to the other surface of the second external terminal.
According to the configuration of the seventh aspect, the semiconductor-chip-mounted intermediate substrates are stacked in layers by the second protrusion electrode and the second outer terminal.
A method for manufacturing the semiconductor device as claimed in claim 7, wherein a first protrusion electrode is formed on a wafer, resin is filled on the surface where said first protrusion electrode is formed, the surface on which said first protrusion electrode on said wafer is not formed is processed so that the thickness of said wafer is thinned, and said wafer is diced into a desired size to form said semiconductor chip. This reduces the length of wiring between semiconductor chips, enabling high-speed signal processing with inductance reduced. Further, stacking semiconductor chips in layers can realize higher density mounting than two-dimensional mounting, enabling manufacturing small-sized and lightweight semiconductor devices and further manufacturing small-sized and lightweight electronic equipment.
Further, a semiconductor chip is processed by grinding, polishing, and etching so that the thickness of the semiconductor chip is reduced. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the eighth aspect of the present invention, the above object is attained by a method for manufacturing the semiconductor device in the configuration of the seventh aspect, wherein a first protrusion electrode is formed on a wafer, resin is filled on the surface where the first protrusion electrode is formed, the surface on which the first protrusion electrode on said wafer is not formed is processed so that the thickness of the wafer is thinned, and the wafer is diced into a desired size to form the semiconductor chips.
According to the configuration of the eighth aspect, a semiconductor chip is processed by grinding, polishing, and etching so that the thickness of the semiconductor chip is reduced. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
Further, filling resin around the first protrusion electrode increases the strength of connection between the first protrusion electrode and the base substrate, thus enabling improving the reliability of the semiconductor device.
According to the eleventh aspect of the present invention, the above object is attained by a method for manufacturing the semiconductor device in the configuration of the seventh aspect, wherein the semiconductor chip is processed so that the thickness of the semiconductor chip is approx. 200 xcexcm or less.
According to the configuration of the eleventh aspect, the semiconductor chip is processed to approx. 200 xcexcm or less. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the twelfth aspect of the present invention, the above object is attained by a method for manufacturing the semiconductor device in the configuration of the seventh aspect, wherein the second protrusion electrode is formed so that the thickness for the multi-layering direction of the intermediate substrate is approx. 300 xcexcm or less.
According to the configuration of the twelfth aspect, the second protrusion electrode is processed to approx. 200 xcexcm or less in the direction of stacking in layers. When the semiconductor chips and intermediate substrates are stacked in layers, the length in the direction of the stacking in layers is not therefore increased, and so the semiconductor device can be both miniaturized and lightened.
According to the thirteenth aspect of the present invention, the above object is attained by a method for manufacturing the semiconductor device in the configuration of the seventh aspect, wherein a third protrusion electrode is formed on the surface of the wafer, resin is filled on the surface where the third protrusion electrode is formed, the tip of the third protrusion electrode is removed and a fourth protrusion electrode is provided on the third protrusion electrode to form the first protrusion electrode.
According to the thirteenth aspect of the present invention, filling resin around the third protrusion electrode increases the strength of connection between the third protrusion electrode and the base substrate improving the reliability of the semiconductor device. Further, the tip of the third protrusion electrode is removed and the fourth protrusion electrode is formed on the third protrusion electrode. Resin attached to the tip of the third protrusion electrode is removed by grinding the tip of the third protrusion electrode to reduce the resistance of connection between the third and fourth protrusion electrodes. Moreover, forming the fourth protrusion electrodes on the third protrusion electrodes by a ball transfer method evens the height of the first protrusion electrodes, thus improving the reliability of flip-chip mounting.
Generally, the forming of the above solder ball bump 7a is performed on the semiconductor wafer, that is, in the state prior to dicing of the wafer into respective semiconductor IC 1 chips.
The semiconductor ICs 1 on whose electrodes the solder bumps 7a are formed in the above manner are diced out of the wafer-shaped semiconductor substrate 2.
Further, the solder ball bumps 7a of respective semiconductor ICs 1 are made abutted on the lands formed on the printed wiring board on which the semiconductor ICs to be mounted.
Consequently, to miniaturize electronic equipment, a substrate is reduced in size, enabling manufacturing smaller-sized and more lightweight electronic equipment.
It is desirable that the space of mounting electronic parts on the substrate is as small as possible for portable electronic equipment such as IC cards, portable telephones, and personal digital assistants (PDAs). The mounting space in electronic equipment must therefore be further reduced in size.
However, in consideration of only two-dimensional space, there is a limit on miniaturization of electronic parts, and so a mounting space must be designed from the viewpoint of not only two-dimensional direction, but also three-dimensional direction. The semiconductor devices for electronic equipment to be reduced in size and weight have therefore been expected.